I am the owner of a 1992 C4 convertible with approximately 51,000 miles on it and have had some intermittent issues with brake lock up. It appears that all four wheels lock when this happens. When this happens, as it did today on a ride, I would have to pull and release the parking brake to get the brakes to release. However, today that didn't work but just pumping the brake pedal a couple of times first and then pulling and releasing the parking brake got them released. The car seemed to be free wheeling as normal when the clutch was engaged but when I returned to my garage and started to clean the road grime off of the wheels, I noticed that the saw tooth wheels were very warm to the touch, not red hot but very warm. I wonder if this was residual heat from when the brakes had locked up or whether the wheels may have released but not quite fully? As I mentioned, the car seemed to be freewheeling ok with no perceptible drag.

I have had the car into the shop of a local corvette guy last year for this problem and after going over the braking system at that time said he couldn't find any issues. He test drove it a couple of times as well and still nothing. Parking brake and brake pedal checked out at that time. I have been reading some other threads with similar issues and am starting to wonder if I may have a master cylinder issue since it is original to the car. All of the brake lines, pads and rotors were given a clean bill of health.

Thoughts anyone????